//=============================================================================
// System  : MatchKit
// File    : CancellationFlag.cs
// Author  : Fabio Bussu  (matchkit@fabiobussu.it)
// Updated : 04/16/2013
// Note    : Copyright 2013, Fabio Bussu, All rights reserved
//
// This code is published under the Microsoft Public License (Ms-PL). A copy
// of the license should be distributed with the code.  It can also be found
// at the project website: http://matchkit.codeplex.com. This notice, the
// author's name, and all copyright notices must remain intact in all
// applications, documentation, and source files.
//
// Version     Date     Who  Comments
// ============================================================================
// 1.0.0.0  04/16/2013   FB  First draft
//=============================================================================
using System;
using System.Collections.Generic;
using System.Runtime.Serialization;
using System.Text;

namespace MatchKit
{
	/// <summary>
	/// Provides a way to abort the matching process.
	/// </summary>
	/// <threadsafety static="true" instance="false" />
	/// <serialization binary="true" contract="true" />
	/// <conceptualLink target="7e399cd8-5aaa-4616-a3c9-abcc9344dabc" />
	/// <conceptualLink target="0a06b2a9-5f58-409a-ba62-639cfd77bca7" />
	#if DC
	[DataContract]
	#endif
	#if SZ
	[Serializable]
	#endif
	public class CancellationFlag
	{
		/// <summary>
		/// Returns an empty CancellationFlag value.
		/// </summary>
		/// <remarks>
		/// The CancellationFlag value returned by this property will be non-cancelable.
		/// </remarks>
		public static CancellationFlag None { get { return new EmptyCancellationFlag(); } }

		/// <summary>
		/// Signals that the matching process should be canceled.
		/// </summary>
		public virtual void Cancel()
		{
			IsCancellationRequested = true;
		}

		/// <summary>
		/// Gets whether cancellation has been requested for this CancellationFlag.
		/// </summary>
		/// <serialization member="true" />
		#if DC
		[DataMember]
		#endif
		public virtual bool IsCancellationRequested { get; private set; }

		class EmptyCancellationFlag : CancellationFlag
		{
			public override bool IsCancellationRequested
			{
				get { return false; }
			}
		}
	}
}
